ultrasecret
/ˌʌltrəˈsikrɪt/
adjective
- Extremely secret; known or shared by only a very few people, often for security reasons.
- The government built an ultrasecret bunker deep underground.
- The spy passed an ultrasecret document hidden inside a book.
- Only three people knew the ultrasecret recipe for the special sauce.
Synonyms